使用 <bpa-input :id="{id}"> 時，需要 <label :for="{id}">
但如果是在 <bpa-form-item :labelFor="{id}"> 裡面時，就不需要加 <label>。
<label for="test">Label</label>
<bpa-input id="test"/>
...
<bpa-form-item :labelFor="test">
<bpa-input id="test"/>
</bpa-form-item><bpa-input v-model="value" size="small"/><bpa-input v-model="value" placeholder="Please enter here!"/><bpa-input v-model="value" disabled/><bpa-input v-model="value" required/><bpa-input v-model="value" readonly/><bpa-input v-model="value" error/><bpa-input v-model="value" accesskey="K"/><bpa-input v-model="value" disabledClear/><!-- password -->
<bpa-input v-model="value" type="password"/>
<!-- multiple lines -->
<bpa-input v-model="value" type="textarea"/>